I am actually working on a service where you can easily deploy VPSs that have Docker installed on them with a control panel for conveniently managing the containers. I can then have features like a menu option to move containers between VMs and automatically creating DNS and proxy configuration for container-based virtual hosting. I.e. you click a button on the container and just type in the sub domain or domain name next to the public port exposed by Docker and then that gets automatically set up so you can access that service on that container through a domain name.